Question

related rates problem. see picture

Answer 1

Would you agree that we can state:
\[x ^{2}+ 7^{2}=s ^{2}\]?

Answer 2

Now we need to differentiate getting dx/dt

2x dx/dt=2s ds/dt
2x dx/dt = 2s 300
\[2\sqrt{51}(dx/dt)=20\times 300=6000\]
\[dx/dt=6000/(2\sqrt{51})\]